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Nazari-Serenjeh F, Sadeghi M, Azizbeigi R, Semizeh H, Mazaheri S, Haghparast A, Haghparast A. Blocking the dopaminergic receptors within the hippocampal dentate gyrus reduced analgesic responses induced by restraint stress in the formalin test. Behav Brain Res 2024; 463:114914. [PMID: 38368953 DOI: 10.1016/j.bbr.2024.114914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/31/2024] [Accepted: 02/15/2024] [Indexed: 02/20/2024]
Abstract
Previous studies have shown that various receptors, including dopamine receptors, are expressed in the hippocampal dentate gyrus (DG). Besides, indicatively, dopamine receptors play an essential role in the modulation of pain perception. On the other hand, stressful experiences can produce analgesia, termed stress-induced analgesia (SIA). The current study examined the probable role of dopamine receptors within the DG in antinociception induced by restraint stress (RS). Ninety-seven male albino Wistar rats were unilaterally implanted with a cannula in the DG. Animals received intra-DG microinjections of SCH23390 or Sulpiride (0.25, 1, and 4 μg/rat) as D1-and D2-like dopamine receptor antagonists, respectively, five minutes before RS. Ten minutes after the end of the induction of RS for three hours, 50 μl 2.5% formalin was injected subcutaneously into the plantar surface of the hind paw to induce persistent inflammatory pain. Pain scores were evaluated at 5-minute intervals for 60 minutes. These findings showed that; exposure to RS for three hours produced SIA in both phases of the formalin test, while this RS-induced analgesia was attenuated in the early and late phases of the formalin test by intra-DG microinjection of SCH23390 and Sulpiride. The results of the present study suggested that both D1- and D2-like dopamine receptors in the DG have a considerable role in the induced analgesia by RS.
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Affiliation(s)
| | - Mehdi Sadeghi
- Department of Physiology, Faculty of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Ronak Azizbeigi
- Department of Basic Sciences, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran
| | - Hadi Semizeh
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sajad Mazaheri
- Neurophysiology Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Haghparast
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abbas Haghparast
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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2
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Okumura T, Nozu T, Ishioh M, Igarashi S, Kumei S, Ohhira M. Centrally administered butyrate improves gut barrier function, visceral sensation and septic lethality in rats. J Pharmacol Sci 2021; 146:183-191. [PMID: 34116731 DOI: 10.1016/j.jphs.2021.04.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/29/2021] [Accepted: 04/21/2021] [Indexed: 12/12/2022] Open
Abstract
Short chain fatty acids readily crosses the gut-blood and blood-brain barrier and acts centrally to influence neuronal signaling. We hypothesized that butyrate, a short-chain fatty acid produced by bacterial fermentation, in the central nervous system may play a role in the regulation of intestinal functions. Colonic permeability and visceral sensation was evaluated in rats. Septic lethality was evaluated in a sepsis model induced by subcutaneous administration of both lipopolysaccharide and colchicine. Intracisternal butyrate dose-dependently improved colonic hyperpermeability and visceral nociception. In contrast, subcutaneous injection of butyrate failed to change it. Intracisternal orexin 1 receptor antagonist or surgical vagotomy blocked the central butyrate-induced improvement of colonic hyperpermeability. The improvement of intestinal hyperpermeability by central butyrate or intracisternal orexin-A was blocked by cannabinoid 1 or 2 receptor antagonist. Intracisternal butyrate significantly improved survival period in septic rats. These results suggest that butyrate acts in the central nervous system to improve gut permeability and visceral nociception through cannabinoid signaling. Endogenous orexin in the brain may mediate the reduction of intestinal hyperpermeability by central butyrate through the vagus nerve. We would suggest that improvement of leaky gut by central butyrate may induce visceral antinociception and protection from septic lethality.
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Affiliation(s)
- Toshikatsu Okumura
- Division of Metabolism, Biosystemic Science, Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan; Department of General Medicine, Asahikawa Medical University, Japan.
| | - Tsukasa Nozu
- Department of Regional Medicine and Education, Asahikawa Medical University, Japan
| | - Masatomo Ishioh
- Division of Metabolism, Biosystemic Science, Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan
| | - Sho Igarashi
- Division of Metabolism, Biosystemic Science, Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan
| | - Shima Kumei
- Department of General Medicine, Asahikawa Medical University, Japan
| | - Masumi Ohhira
- Department of General Medicine, Asahikawa Medical University, Japan
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3
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Okumura T, Ishioh M, Nozu T. Central regulatory mechanisms of visceral sensation in response to colonic distension with special reference to brain orexin. Neuropeptides 2021; 86:102129. [PMID: 33636498 DOI: 10.1016/j.npep.2021.102129] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/08/2021] [Accepted: 02/09/2021] [Indexed: 01/22/2023]
Abstract
Visceral hypersensitivity is a major pathophysiology in irritable bowel syndrome (IBS). Although brain-gut interaction is considered to be involved in the regulation of visceral sensation, little had been known how brain controls visceral sensation. To improve therapeutic strategy in IBS, we should develop a novel approach to control visceral hypersensitivity. Here, we summarized recent data on central control of visceral sensation by neuropeptides in rats. Orexin, ghrelin or oxytocin in the brain is capable of inducing visceral antinociception. Dopamine, cannabinoid, adenosine, serotonin or opioid in the central nervous system (CNS) plays a role in the visceral hyposensitivity. Central ghrelin, levodopa or morphine could induce visceral antinociception via the orexinergic signaling. Orexin induces visceral antinociception through dopamine, cannabinoid, adenosine or oxytocin. Orexin nerve fibers are identified widely throughout the CNS and orexins are implicated in a number of functions. With regard to gastrointestinal functions, in addition to its visceral antinociception, orexin acts centrally to stimulate gastrointestinal motility and improve intestinal barrier function. Brain orexin is also involved in regulation of sleep/awake cycle and anti-depressive action. From these evidence, we would like to make a hypothesis that decreased orexin signaling in the brain may play a role in the pathophysiology in a part of patients with IBS who are frequently accompanied with sleep disturbance, depressive state and disturbed gut functions such as gut motility disturbance, leaky gut and visceral hypersensitivity.
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Affiliation(s)
- Toshikatsu Okumura
- Division of Metabolism, Biosystemic Science, Gastroenterology and Hematology/Oncology, Department of Medicine, Japan.
| | - Masatomo Ishioh
- Division of Metabolism, Biosystemic Science, Gastroenterology and Hematology/Oncology, Department of Medicine, Japan
| | - Tsukasa Nozu
- Department of Regional Medicine and Education, Asahikawa Medical University, Japan
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4
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Ishioh M, Nozu T, Igarashi S, Tanabe H, Kumei S, Ohhira M, Takakusaki K, Okumura T. Activation of central adenosine A2B receptors mediate brain ghrelin-induced improvement of intestinal barrier function through the vagus nerve in rats. Exp Neurol 2021; 341:113708. [PMID: 33771554 DOI: 10.1016/j.expneurol.2021.113708] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/15/2021] [Accepted: 03/21/2021] [Indexed: 11/16/2022]
Abstract
Leaky gut that is a condition reflecting intestinal barrier dysfunction has been attracting attention for its relations with many diseases such as irritable bowel syndrome or Alzheimer dementia. We have recently demonstrated that ghrelin acts in the brain to improve leaky gut via the vagus nerve. In the present study, we tried to clarify the precise central mechanisms by which ghrelin improves intestinal barrier function through the vagus nerve. Colonic permeability was estimated in vivo by quantifying the absorbed Evans blue in colonic tissue in rats. Adenosine receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX), blocked the intracisternal ghrelin-induced improvement of intestinal hyperpermeability while dopamine, cannabinoid or opioid receptor antagonist failed to prevent it. Since DPCPX can block adenosine A1 and adenosine A2B receptors, we examined which subtype is involved in the mechanism. Intracisternal injection of adenosine A2B agonist but not adenosine A1 agonist improved colonic hyperpermeability, while peripheral injection of adenosine A2B agonist failed to improve it. Intracisternal adenosine A2B agonist-induced improvement of colonic hyperpermeability was blocked by vagotomy. Adenosine A2B specific antagonist, alloxazine blocked the ghrelin- or central vagal stimulation by 2-deoxy-d-glucose-induced improvement of intestinal hyperpermeability. These results suggest that activation of adenosine A2B receptors in the central nervous system is capable of improving intestinal barrier function through the vagal pathway, and the adenosine A2B receptors may mediate the ghrelin-induced improvement of leaky gut in a vagal dependent fashion. These findings may help us understand the pathophysiology in not only gastrointestinal diseases but also non-gastrointestinal diseases associated with the altered intestinal permeability.
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Affiliation(s)
- Masatomo Ishioh
- Division of Metabolism, Systemic Bioscience, Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan; Department of General Medicine, Asahikawa Medical University, Japan
| | - Tsukasa Nozu
- Department of Regional Medicine and Education, Asahikawa Medical University, Japan
| | - Sho Igarashi
- Division of Metabolism, Systemic Bioscience, Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan
| | - Hiroki Tanabe
- Division of Metabolism, Systemic Bioscience, Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan
| | - Shima Kumei
- Department of General Medicine, Asahikawa Medical University, Japan
| | - Masumi Ohhira
- Department of General Medicine, Asahikawa Medical University, Japan
| | - Kaoru Takakusaki
- Division of Neuroscience, Department of Physiology, Asahikawa Medical University, Japan
| | - Toshikatsu Okumura
- Division of Metabolism, Systemic Bioscience, Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan; Department of General Medicine, Asahikawa Medical University, Japan.
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Adenosine A1 receptor agonist induces visceral antinociception via 5-HT1A, 5-HT2A, dopamine D1 or cannabinoid CB1 receptors, and the opioid system in the central nervous system. Physiol Behav 2020; 220:112881. [DOI: 10.1016/j.physbeh.2020.112881] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 03/17/2020] [Accepted: 03/17/2020] [Indexed: 02/08/2023]
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6
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Nozu T, Miyagishi S, Nozu R, Takakusaki K, Okumura T. Losartan improves visceral sensation and gut barrier in a rat model of irritable bowel syndrome. Neurogastroenterol Motil 2020; 32:e13819. [PMID: 32056324 DOI: 10.1111/nmo.13819] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/03/2020] [Accepted: 01/22/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Lipopolysaccharide (LPS) or repeated water avoidance stress (WAS) induces visceral allodynia and colonic hyperpermeability via corticotropin-releasing factor (CRF) and proinflammatory cytokines, which is considered to be a rat irritable bowel syndrome (IBS) model. As losartan is known to inhibit proinflammatory cytokine release, we hypothesized that it improves these visceral changes. METHODS The threshold of visceromotor response (VMR), that is, abdominal muscle contractions induced by colonic balloon distention was electrophysiologically measured in rats. Colonic permeability was determined in vivo by quantifying the absorbed Evans blue in colonic tissue for 15 minutes spectrophotometrically. KEY RESULTS Lipopolysaccharide (1 mg kg-1 ) subcutaneously (s.c.) reduced the threshold of VMR and increased colonic permeability. Losartan (5-25 mg kg-1 s.c.) for 3 days inhibited these changes in a dose-dependent manner. Moreover, repeated WAS (1 hour daily for 3 days) or intraperitoneal injection of CRF (50 µg kg-1 ) induced the similar visceral changes as LPS, which were also eliminated by losartan. These effects by losartan in LPS model were reversed by GW9662 (a peroxisome proliferator-activated receptor-γ [PPAR-γ] antagonist), NG -nitro-L-arginine methyl ester (a nitric oxide [NO] synthesis inhibitor), or naloxone (an opioid receptor antagonist). Moreover, it also inhibited by sulpiride (a dopamine D2 receptor antagonist) or domperidone (a peripheral dopamine D2 antagonist). CONCLUSION & INFERENCES Losartan prevented visceral allodynia and colonic hyperpermeability in rat IBS models. These actions may be PPAR-γ-dependent and also mediated by the NO, opioid, and dopamine D2 pathways. Losartan may be useful for IBS treatment.
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Affiliation(s)
- Tsukasa Nozu
- Department of Regional Medicine and Education, Asahikawa Medical University, Asahikawa, Japan.,Center for Medical Education, Asahikawa Medical University, Asahikawa, Japan
| | - Saori Miyagishi
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Asahikawa, Japan
| | - Rintaro Nozu
- Department of Regional Medicine and Education, Asahikawa Medical University, Asahikawa, Japan
| | - Kaoru Takakusaki
- Research Center for Brain Function and Medical Engineering, Asahikawa Medical University, Asahikawa, Japan
| | - Toshikatsu Okumura
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Asahikawa, Japan.,Department of General Medicine, Asahikawa Medical University, Asahikawa, Japan
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7
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5-HT2A receptors but not cannabinoid receptors in the central nervous system mediate levodopa-induced visceral antinociception in conscious rats. Naunyn Schmiedebergs Arch Pharmacol 2020; 393:1419-1425. [DOI: 10.1007/s00210-020-01842-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 02/14/2020] [Indexed: 12/12/2022]
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8
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Fakhoury M, Salman I, Najjar W, Merhej G, Lawand N. The Lateral Hypothalamus: An Uncharted Territory for Processing Peripheral Neurogenic Inflammation. Front Neurosci 2020; 14:101. [PMID: 32116534 PMCID: PMC7029733 DOI: 10.3389/fnins.2020.00101] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/24/2020] [Indexed: 12/20/2022] Open
Abstract
The roles of the hypothalamus and particularly the lateral hypothalamus (LH) in the regulation of inflammation and pain have been widely studied. The LH consists of a parasympathetic area that has connections with all the major parts of the brain. It controls the autonomic nervous system (ANS), regulates feeding behavior and wakeful cycles, and is a part of the reward system. In addition, it contains different types of neurons, most importantly the orexin neurons. These neurons, though few in number, perform critical functions such as inhibiting pain transmission and interfering with the reward system, feeding behavior and the hypothalamic pituitary axis (HPA). Recent evidence has identified a new role for orexin neurons in the modulation of pain transmission associated with several inflammatory diseases, including rheumatoid arthritis and ulcerative colitis. Here, we review recent findings on the various physiological functions of the LH with special emphasis on the orexin/receptor system and its role in mediating inflammatory pain.
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Affiliation(s)
- Marc Fakhoury
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Israa Salman
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Wassim Najjar
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - George Merhej
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Nada Lawand
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Department of Neurology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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9
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Butyrate inhibits visceral allodynia and colonic hyperpermeability in rat models of irritable bowel syndrome. Sci Rep 2019; 9:19603. [PMID: 31862976 PMCID: PMC6925246 DOI: 10.1038/s41598-019-56132-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 12/06/2019] [Indexed: 12/11/2022] Open
Abstract
Lipopolysaccharide (LPS) or repeated water avoidance stress (WAS) induces visceral allodynia and gut hyperpermeability via corticotropin-releasing factor (CRF) and proinflammatory cytokines, which is a rat irritable bowel syndrome (IBS) model. As butyrate is known to suppress the release of proinflammatory cytokine, we hypothesized that butyrate alleviates these colonic changes in IBS models. The visceral pain was assessed by electrophysiologically measuring the threshold of abdominal muscle contractions in response to colonic distention. Colonic permeability was determined by measuring the absorbance of Evans blue in colonic tissue. Colonic instillation of sodium butyrate (SB; 0.37-2.9 mg/kg) for 3 days inhibited LPS (1 mg/kg)-induced visceral allodynia and colonic hyperpermeability dose-dependently. Additionally, the visceral changes induced by repeated WAS (1 h for 3 days) or CRF (50 µg/kg) were also blocked by SB. These effects of SB in the LPS model were eliminated by compound C, an AMPK inhibitor, or GW9662, a PPAR-γ antagonist, NG-nitro-L-arginine methyl ester, a NO synthesis inhibitor, naloxone or sulpiride. SB attenuated visceral allodynia and colonic hyperpermeability in animal IBS models. These actions may be AMPK and PPAR-γ dependent and also mediated by the NO, opioid and central dopamine D2 pathways. Butyrate may be effective for the treatment of IBS.
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10
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Lomax AE, Pradhananga S, Sessenwein JL, O'Malley D. Bacterial modulation of visceral sensation: mediators and mechanisms. Am J Physiol Gastrointest Liver Physiol 2019; 317:G363-G372. [PMID: 31290688 DOI: 10.1152/ajpgi.00052.2019] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The potential role of the intestinal microbiota in modulating visceral pain has received increasing attention during recent years. This has led to the identification of signaling pathways that have been implicated in communication between gut bacteria and peripheral pain pathways. In addition to the well-characterized impact of the microbiota on the immune system, which in turn affects nociceptor excitability, bacteria can modulate visceral afferent pathways by effects on enterocytes, enteroendocrine cells, and the neurons themselves. Proteases produced by bacteria, or by host cells in response to bacteria, can increase or decrease the excitability of nociceptive dorsal root ganglion (DRG) neurons depending on the receptor activated. Short-chain fatty acids generated by colonic bacteria are involved in gut-brain communication, and intracolonic short-chain fatty acids have pronociceptive effects in rodents but may be antinociceptive in humans. Gut bacteria modulate the synthesis and release of enteroendocrine cell mediators, including serotonin and glucagon-like peptide-1, which activate extrinsic afferent neurons. Deciphering the complex interactions between visceral afferent neurons and the gut microbiota may lead to the development of improved probiotic therapies for visceral pain.
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Affiliation(s)
- Alan E Lomax
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Sabindra Pradhananga
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Jessica L Sessenwein
- Gastrointestinal Diseases Research Unit, Queen's University, Kingston, Ontario, Canada
| | - Dervla O'Malley
- APC Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Physiology, University College Cork, Cork, Ireland
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Dehydroepiandrosterone sulfate improves visceral sensation and gut barrier in a rat model of irritable bowel syndrome. Eur J Pharmacol 2019; 852:198-206. [DOI: 10.1016/j.ejphar.2019.03.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/15/2019] [Accepted: 03/22/2019] [Indexed: 02/07/2023]
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12
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Okumura T, Nozu T, Kumei S, Ohhira M. Central oxytocin signaling mediates the central orexin-induced visceral antinociception through the opioid system in conscious rats. Physiol Behav 2019; 198:96-101. [DOI: 10.1016/j.physbeh.2018.10.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/11/2018] [Accepted: 10/11/2018] [Indexed: 02/08/2023]
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Nozu T, Miyagishi S, Kumei S, Nozu R, Takakusaki K, Okumura T. Metformin inhibits visceral allodynia and increased gut permeability induced by stress in rats. J Gastroenterol Hepatol 2019; 34:186-193. [PMID: 29966173 DOI: 10.1111/jgh.14367] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/06/2018] [Accepted: 06/17/2018] [Indexed: 12/23/2022]
Abstract
BACKGROUND AND AIM Metformin has been shown to have anti-cytokine property. Lipopolysaccharide (LPS)-induced or repeated water avoidance stress (WAS)-induced visceral allodynia and increased gut permeability were pro-inflammatory cytokine-dependent responses, which were considered to be animal models of irritable bowel syndrome (IBS). We hypothesized that metformin improves symptoms in the patients with IBS by attenuating these visceral changes and tested the hypothesis in rats. METHODS The threshold of the visceromotor response induced by colonic balloon distention was measured. Colonic permeability was determined in vivo by quantifying the absorbed Evans blue for 15 min spectrophotometrically. RESULTS Subcutaneously injected LPS (1 mg/kg) reduced the threshold of visceromotor response, and metformin (5-50 mg/kg for 3 days) intraperitoneally attenuated this response in a dose-dependent manner. Repeated WAS (1 h daily for 3 days) induced visceral allodynia, which was also blocked by metformin. The antinociceptive effect of metformin on the LPS-induced allodynia was reversed by compound C, an adenosine monophosphate-activated protein kinase inhibitor or NG -nitro-L-arginine methyl ester, a nitric oxide synthesis inhibitor but not modified by naloxone. Additionally, it was blocked by sulpiride, a dopamine D2 receptor antagonist, but domperidone, a peripheral dopamine D2 receptor antagonist, did not alter it. Metformin also blocked the LPS-induced or repeated WAS-induced increased colonic permeability. CONCLUSIONS Metformin attenuated the visceral allodynia and increased gut permeability in animal IBS models. These actions may be evoked via activation of adenosine monophosphate-activated protein kinase, nitric oxide, and central dopamine D2 pathways. These results indicate the possibility that metformin can be useful for treating IBS.
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Affiliation(s)
- Tsukasa Nozu
- Department of Regional Medicine and Education, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Saori Miyagishi
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Shima Kumei
- Department of General Medicine, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Rintaro Nozu
- Department of Regional Medicine and Education, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Kaoru Takakusaki
- Research Center for Brain Function and Medical Engineering, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
| | - Toshikatsu Okumura
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Asahikawa, Hokkaido, Japan.,Department of General Medicine, Asahikawa Medical University, Asahikawa, Hokkaido, Japan
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14
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Okumura T, Nozu T, Kumei S, Takakusaki K, Ohhira M. Ghrelin acts centrally to induce an antinociceptive action during colonic distension through the orexinergic, dopaminergic and opioid systems in conscious rats. Brain Res 2018; 1686:48-54. [DOI: 10.1016/j.brainres.2018.02.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 02/06/2018] [Accepted: 02/17/2018] [Indexed: 02/08/2023]
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15
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Razavi BM, Hosseinzadeh H. A review of the role of orexin system in pain modulation. Biomed Pharmacother 2017; 90:187-193. [DOI: 10.1016/j.biopha.2017.03.053] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/15/2017] [Accepted: 03/20/2017] [Indexed: 10/19/2022] Open
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16
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Nozu T, Miyagishi S, Nozu R, Takakusaki K, Okumura T. Water avoidance stress induces visceral hyposensitivity through peripheral corticotropin releasing factor receptor type 2 and central dopamine D2 receptor in rats. Neurogastroenterol Motil 2016; 28:522-31. [PMID: 26662216 DOI: 10.1111/nmo.12747] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/11/2015] [Indexed: 02/08/2023]
Abstract
BACKGROUND Water avoidance stress (WAS) is reported to induce functional changes in visceral sensory function in rodents, but the results which have been demonstrated so far are not consistent, i.e., hypersensitivity or hyposensitivity. We determined the effect of WAS on visceral sensation and evaluated the mechanisms of the action. METHODS Visceral sensation was assessed by abdominal muscle contractions induced by colonic balloon distention, i.e., visceromotor response (VMR), measured electrophysiologically in conscious rats. The electromyogram electrodes were acutely implanted under anesthesia on the day of the experiment. The threshold of VMR was measured before and after WAS for 1 h. To explore the mechanisms of WAS-induced response, drugs were administered 10 min prior to the initiation of WAS. KEY RESULTS WAS significantly increased the threshold of VMR, and this effect was no longer detected at 24 h after. Intraperitoneal injection of astressin2 -B (200 μg/kg), a corticotropin releasing factor (CRF) receptor type 2 antagonist abolished the response by WAS. Subcutaneous (sc) injection of sulpiride (200 mg/kg), a dopamine D2 receptor antagonist blocked the response, while sc domperidone (10 mg/kg), a peripheral dopamine D2 receptor antagonist did not alter it. Naloxone (1 mg/kg, sc), an opioid antagonist did not modify it either. CONCLUSIONS & INFERENCES WAS induced visceral hyposensitivity through peripheral CRF receptor type 2 and central dopamine D2 receptor, but not through opioid pathways. As altered pain inhibitory system was reported to be observed in the patients with irritable bowel syndrome, CRF and dopamine signaling might contribute to the pathophysiology.
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Affiliation(s)
- T Nozu
- Department of Regional Medicine and Education, Asahikawa Medical University, Asahikawa, Japan
| | - S Miyagishi
- Department of General Medicine, Asahikawa Medical University, Asahikawa, Japan
| | - R Nozu
- Department of Regional Medicine and Education, Asahikawa Medical University, Asahikawa, Japan
| | - K Takakusaki
- Research Center for Brain Function and Medical Engineering, Asahikawa Medical University, Asahikawa, Japan
| | - T Okumura
- Department of General Medicine, Asahikawa Medical University, Asahikawa, Japan
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17
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Adenosine A1 receptors mediate the intracisternal injection of orexin-induced antinociceptive action against colonic distension in conscious rats. J Neurol Sci 2016; 362:106-10. [DOI: 10.1016/j.jns.2016.01.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 01/13/2016] [Accepted: 01/18/2016] [Indexed: 12/12/2022]
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18
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Okumura T, Nozu T, Kumei S, Takakusaki K, Miyagishi S, Ohhira M. Levodopa acts centrally to induce an antinociceptive action against colonic distension through activation of D2 dopamine receptors and the orexinergic system in the brain in conscious rats. J Pharmacol Sci 2016; 130:123-7. [DOI: 10.1016/j.jphs.2016.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 12/24/2015] [Accepted: 01/20/2016] [Indexed: 02/08/2023] Open
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